Conventional ground-based, man-portable Target Location Systems (TLS) exist in the U.S. Armed Services inventory. Representative examples include the Lightweight Laser Detector and Rangefinder (LLDR) and the Mark VII that are used for measuring stationary target positions. These systems generally use optical instrumentation for focusing and aiming for both night and day operations. They also employ laser rangefinders, magnetometers and inclinometers to measure range, azimuth and inclination. Typically, the operator turns the system on, goes through a relatively elaborate and tedious procedure of calibrating the magnetometer, lets the GPS acquisition complete, lets the camera warm up, focuses the camera on the target, places the crosshairs on the target aim point and pulls the trigger, which initiates the laser rangefinder to engage. The range, azimuth and inclination are then measured and processed in a GPS receiver to estimate target coordinates. The accuracy of the range finders are generally good; however, the accuracies of the magnetometers and inclinometers are marginal at best—generally resulting in large target position errors, especially at long ranges. To accommodate targeting errors, weapons with terminal seekers or weapons with large warheads have been employed. Both of these conventional solutions, however, are unsatisfactory because seekers are complex and expensive, while large warheads generally cause unnecessary collateral damage.
Some conventional target location systems that are mounted on specially designed tripods (for slewing and target tracking) have not been fully utilized because they have been designed for acquisition of stationary targets only. Precision attacks against moving targets with GPS guided weapons generally require that the weapons receive accurate data of predicted target position for a particular weapon intercept time with minimum delay. One way of accomplishing this has been to use conventional systems to estimate target velocity, predict target position at a given intercept time and uplink this data to an incoming weapon via a data link for terminal guidance.
That notwithstanding, there remains a need to reduce TLS angular errors, to improve target location accuracy, to mitigate the need for elaborate and tedious calibration procedures, to reduce the need for expensive weapons with terminal seekers, and to minimize collateral damage. Additionally, there is a need to more effectively utilize target location systems to conduct precision attacks on moving targets by accurately predicting moving target positions for a given weapon intercept time.